
package com.liu.LiuRule;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 * 负载均衡的算法
 */
public class LiuRandomRule extends AbstractLoadBalancerRule {

    //每个机器，访问5次，换下一个服务

    //total=0,默认=0.如果=5，我们指向下一个节点

    //index=0,默认0，如果total=5，index+1


    private int total = 0;//被调用的次数
    private int currIndex = 0;//当前是谁在提供服务


    public LiuRandomRule() {
    }

    @SuppressWarnings({"RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE"})
    public Server choose(ILoadBalancer lb, Object key) {
        if (lb == null) {
            return null;
        } else {
            Server server = null;

            while(server == null) {
                if (Thread.interrupted()) {
                    return null;
                }

                //获得活着的服务
                List<Server> upList = lb.getReachableServers();
                //获得全部的服务
                List<Server> allList = lb.getAllServers();

                int serverCount = allList.size();
                if (serverCount == 0) {
                    return null;
                }
                //生成区间随机数
                //int index = this.chooseRandomInt(serverCount);
                //从活着的服务中随机获取
                //server = (Server)upList.get(index);


                if(total<5){
                    server = upList.get(currIndex);
                    total++;
                }else{
                    total = 0;
                    currIndex++;
                    if(currIndex>upList.size()){
                        currIndex = 0;
                    }
                    server = upList.get(currIndex); //从活着的服务中获取指定的服务来进行操作
                }

                if (server == null) {
                    Thread.yield();
                } else {
                    if (server.isAlive()) {
                        return server;
                    }
                    server = null;
                    Thread.yield();
                }
            }

            return server;
        }
    }

    protected int chooseRandomInt(int serverCount) {
        return ThreadLocalRandom.current().nextInt(serverCount);
    }

    public Server choose(Object key) {
        return this.choose(this.getLoadBalancer(), key);
    }

    public void initWithNiwsConfig(IClientConfig clientConfig) {
    }
}
